The present invention relates generally to a method and apparatus for manufacturing reusable paint rollers.
Paint rollers are frequently used by professional painters and non-professional painters to apply a layer of paint to walls, ceilings, and other surfaces. Paint rollers increase the painter's efficiency by permitting the paint to be applied much more rapidly than is possible by using a conventional paint brush.
Paint rollers typically include a core and a paint absorbing outer fabric layer or cover. The core may be solid preformed stock material, or may be wound from one or more strips of base material. An example of a known paint roller is disclosed in U.S. Pat. No. 4,692,975 issued to Garcia. Garcia uses a core comprised of a preformed tube of solid thermoplastic material. A moveable platform applies a continuous strip of fabric to the rotating core. The core is partially melted just prior to application of the fabric material such that the fabric becomes permanently bonded to the core. However, this technique is expensive, as preformed stock material is required.
Another example of a known paint roller is disclosed in U.S. Pat. No. 5,572,790 issued to Sekar. Sekar discloses using multiple strips of thermoplastic material, which are wound about a stationary mandril to form a core. Once the core is formed, additional liquid thermoplastic material is applied to the core to act as an adhesive to bond the fabric material to the core, which is then also wound about the core. However, Sekar has several disadvantages. Liquid thermoplastic material must be applied to the core from one or more feed nozzles, or other type of device capable of accurately applying the liquid "adhesive." It is difficult to accurately regulate the application of liquid thermoplastic material from the application nozzle to the rotating core. Such nozzles often clog, thus causing the manufacturing process to be temporarily halted until the nozzle is cleaned. Additionally, such a process is expensive because the multiple nozzle system is costly to operate and maintain. Several such nozzles must be used if multiple strips of material are wound to form the core. Typically, one application nozzle is used for each strip of base material, in addition to one nozzle for applying the liquid thermoplastic material to the fabric strip.
In Sekar, the base material that forms the core is made of strips of thermoplastic material, such as polypropylene. Cores formed of only thermoplastic strips of material tend to be weaker than cores formed of other material, such as metal and cardboard strips, thus the useful life of such paint rollers is relatively short.
Accordingly, it is an object of the present invention to provide a novel method of making a paint roller to substantially overcome the above-described problems.
It is another object of the present invention to provide a novel method of making a paint roller that does not use thermoplastic strips as the base material from which to form the core.
It is a further object of the present invention to provide a novel method of making a paint roller that uses cardboard or metal strips as the base material for the core.
It is also an object of the present invention to provide a novel method of making a paint roller that does not require application of any adhesive or liquid thermoplastic material to the core once the core has been formed.
It is still an object of the present invention to provide a novel method of making a paint roller where cardboard or metal strips pass through an extruder that applies a layer of liquid thermoplastic material to the strips before the strips are wound to form the core.
It is another object of the present invention to provide a novel method of making a paint roller that uses a heating device to soften and partially melt a pre-manufactured strip of thermoplastic material so as to adhere it to the strips of base material.